My invention relates to catalytic converters for internal combustion engines and specially those with monolithic catalyst elements. A monolithic catalyst element generally comprises a catalyst substance distributed within a one piece, rigid member having an internal structure filled with numerous flow paths for the circulation of exhaust gas through the element. Such an element contained within a casing with input and output means for the exhaust gases comprises a monolithic catalytic converter.
The mounting of such an element within a casing, however, is not simple, since the catalytic converter mounted on a motor vehicle is liable to be subjected to severe shocks and vibrations with resultant chipping or breakage of the monolithic element. The element must therefore be held tightly within the casing; however, allowance must be made for the differing rates of expansion of the element substrate material and the casing over the wide range of temperatures to which catalytic converters are subjected.
A spring between the element and the casing will hold them together during shock or vibration and yet allow relative movement due to differing rates of thermal expansion. However, springs able to withstand the high temperatures encountered within catalytic converters must be made from special, high cost alloys. It is desirable to produce a spring loaded monolithic catalytic converter in which the spring is so protected from the heat within the converter that a common, low cost spring can be used.